Party-line exchange.



N. E. NORSTROM.

PARTY LINE EIGHANGE.

urucnmx rum) no. 1909.

1,1 14,379. Patented Oct. 20, 19m

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N. B. Noasmom.

PARTY LINE EXCHANGE.

APPLIOATIO! FILED IAY 29. 1909.

1,1 14,379. Patented 00a. 20, 1914.

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N. E. NORSTROM.

PARTY LINE EXGHANGB.

nruonmn mum in 29. 1909.

Patented Oct. 20, 1914.

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N. E. NOB-STROM.

PARTY LINE EXCHANGE.

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1,114,379. Patented 001;.20, 1914 4 SKEETB-BHBET 4 m: will "run an.MLITI11\.IAINIIGM. 0 c.

UNITED STATES PATENT OFFICE.

NILS EMEL NOBSTROM, OF CHICAGO, ILLINOIS, ASSIGNOB TO THE ANDERSONELECTRIC AND MANUFACTURING COMPANY, OF MoPHERSON, KANSAS, A CORPORATIONOF KANSAS.

PARTY-LINE EXCHANGE.

Specification of Letters Patent.

Patented Oct. 20, 1914.

Application filed May 29. 1909. Serial No. 499,250.

To all whom it may concern:

Be it known that I, Nns Exam. Nons'rnoM, a citizen of the United Statesof America, and aresident of Chicago, county of Cook, and State ofIllinois, have invented certain new and useful Improvements in Party-Line Exchanges, of which the following is a specification.

My invention relates to party line tele- Zlphone exchanges, and has forits object improvements in such exchanges, and particularly in theconstruction and operation of the apparatus located at the severalsubstations.

The apparatus at the central office may be like that shown in my PatentNo. 877,727, issued January .28, 1908, or like that shown in my PatentNumber 935,049, issued Sept. 28, 190.). In an apparatus of this kindthere is a callin device arranged to be mani ulatcd by the operator atthe central o co. This calling device may beset in advance for anydesired station or stations on a party line and afterward manipulated bturnin a crank or moving a lever. hen sue crank or lever is moved itmakes a series of electrical contacts, one for each station on the line,the result of which is to send over the line a corresponding number ofimpulses. At the instant when an impulse is thus sent for a station forwhich the device had been previously set, a secondary impulse is sentover the line, the effect of which is to connect the desired stationtelephonically l to the line. The details of such central 0 cc apparatusdo not form a part of the resent application, but they are thusdescribed in brief l'lOCflllHC the impulses so sent control theoperation of the apparatus, which will be described.

In the accompanying drawings,-Figure 1 is a front elevation of theswitching apparatus located at each sub-station, a portion of the topplate of this apparatus being removed so as to expose the arts beneath;Fig. 2 is a side elevation of *ig. 1; Fi 3 is an enlarged view similarto Fi 1, lit with some additional parts removed: for the purpose ofshowing details of construction; Fig. 4 is an enlarged section on line44 of Fig. 1; Fig. 5 is a section on line 5-5 of Fig.

1, showing only a few parts; Fig. 6 is a view showing some of tie partsof Fig. 1

detached, so that they may be seen separated from accompanying parts;Fig. 7 is a detail section through the ratchet wheel, by which theswitching mechanism is operated; Fig. 8 is a detail showing the lowerend of the armature lever, the pawl thereon and contact operated by themovement of said lever;

Fig. 9 is a. detail showing the attachment of the permanent magnet; Fig.10 is a transverse section of the signal lever shown in the upper frontpart of Fig. 1; and Fig. 11 is a diagram of two substations on a partyline, the jack for which is shown at the left and is assumed to be inthe central oflice to which the central oiiice apparatus is connected bymeans of an ordinary cord and plug.

In the said drawings, 40 is a sheet metal base, on the upper edge ofwhich is supported an electromagnet M provided with an armature MSecured to-the centrally pivoted armature M is an armature lever 41having a pawl 42. at its lower extremity. This pawl engages the ratchetwheel 43 mounted on a central spindle 44 and serves to rotate said wheelwhen the armature lever is pushed toward the left, as shown in Figs. 1and 3. When the armature lever is moved to the right the bent portionthereof thrusting against the fixed post 45 raises the pawl 42 out ofthe wheel 43 and permits said wheel to be returned to its normal endposition by means of a spring 46 which surrounds the spindle 44. On thebottom face of the wheel 43 is a pin 47 which strikes against anadjustable pin 48 when the wheel 43 reaches its normal position on suchbackward movement. The normal position of the wheel 43 is thusdetermined by contact between the pin 47 and the stop 48, and this stopis adjusted so as to leave a slight clearance between the pawl 42 andthe projection 49 on the wheel 43. The reason for this is that, whilethe spring 46 for returning the wheel 43 to normal position is intedcdto be as light as possible so as to reduce the power required to operatethe magnet M and consequently the amount of current that must be sentover a long line to operate a number of such magnets, the spring 15might be still lighter, with the result that if the projection 49 ispressed a ainst pawl 42 when in normal position the electricalconnection between 15 and 16 would be open when it should be closed. Theadjustable character of the stop 48 permits the clearance between i2 and49 to be adjusted to any degree of fineness.

The wheel 43 maybe secured to the spindle -14 in any convenient manner,but preferably is pressed thereon. Between the wheel 43 and a shoulderon a spindle 14, as shown in Fig. 7, is a spring piece 50, having apiece of insulation 51 on the outside end. The piece 50 is in the formof a fork, as shown in Fig. 3, and consequently may he slipped out ofposition, but is normally held in position by a considerable friction.It may also be rotated by hand and set at any given position on thewheel 43 with respect to the projection 49 thereon.

Secured at a convenient place on the frame 10 are two insulated contacts )rings 26 and 27, one of which has its end in the path of theinsulated piece 51. The springs .26 and 27 are normally out of contactwith each other, but when the insulated portion strikes the bent end ofthe sprin 2G by reason of the rotation of the wheel 43, the said spring26 is pushed into electrical connection with the sprin 27. Thiselectrical connection exists only during one step of the ratchet wheel43. At all steps prior to this contact or thereafter the electricalconnections between 26 and 27 are open. At the different stations on theparty line the piece 50 is adjusted so that the insulated end 51 will bea different distance from the projection 49. For example, in station No.1 the insulated portion 51 will strike the pin 26 when the ratchet wheelhas moved one step. At station No. 2 the insulated portion will strikethe pin when the ratchet wheel has moved two steps, and so on. As willbe hereinafter described, the ratchet wheels of stations move forwardsimultaneously with the result that the electrical connection between 26and 27 are made at the diil'erent stations successively and correspondto the impulses sent out from the central ollice by the operatormanipulatin an instrument such as previously described.

A portion of the spindle 44 is cut away on one side, as shown at 52, inFi s. 3 and 7. At a convenient place on the rame are supported threesprings 3, 4 and 21. The middle spring 3 has a piece of insulation onthe end which rests in this cut-out place 52, when the ratchet wheel isin its normal position. In this condition the spring 3 engages thecontact sprin 4, but when the ratchet wheel 43 and its spindle 44 areturned, the cut-away portion 52 acts as a cam on the end of spring 3 andpushes it away from the contact spring 4 in connection with the contactspring 21. \Vhcn the apparatus returns to normal position theconnections are restored to the position shown in Fig. 3. On thearmature lever 41, as shown in Fig. 8, is a pin 53, which lies betweenpieces of insulation secured to springs 15 and 17. In normal positionthe springs 15 and 17 make electrical connection with the centralportion 16, but when the armature lever 41 is moved in either directionit presses against the insulation on the end of the springs 15 and 17according to the direction of movement and breaks the connection betweenthe moved spring and the fixed part 16. The construction of these isshown in Figs. 5 and 8 in more detail than in the other fi ures. On thefixed part 16 is a pin 54 on which is pivoted a signaling lever 55, oneportion of which is dark or colored and the other portion of which islight, as shown in Fig. 1. The lower end of the signaling lever 55 endsin a fork which embraces the movable pin 53. The view, as shown in Fig.1, shows the switching apparatus at normal )osition with the light partof the signaling lever at the central part of the apparatus. Thisapparatus is presumed to be in a box with a peep-hole opposite thiscentral part so it may be seen whether the line is in use or not. Whenwe consider the apparatus in the position shown in Fi 1, if the armaturelever 41 moves to the left to advance the ratchet wheel the pin willstrike one tine of the fork on the signaling lever 55 and throw it tothe reverse position with the dark part at the upper end of the centerof the apparatus. If the lever were at the other position, the movementof the pin 53 to the right would strike the. other time of the fork andthrow the lever to the position shown in Fig. 1. In the upper part ofthis lever 55 is a slot 56, in which is a sliding weight 57. Assumingthe apparatus in the position shown in Fig. 1, if a movement 0 thearmature lever to the left throws the upper end of the signaling leverto the right, the sudden stopping of this lever The weight 57 i willresult as a rebound. very loosely carried on the slot 50 and continuesto move in the said slot after the lever itself has stopped andcommenced to re bound. The movement of this weight 57 against therebound or lever itself will prevent the RibOllTKl of this signalinglever amounting to enough to affect the apparatus. In other words, thissliding weight in this piece very perceptibly lessens the reboundresulting from the sudden stopping of the signaling lever when thrown toeither the right or the left. A similar apparatus is shown at 58 in theratchet wheel 43 for preventing rebound of that wheel when returning tonormal position.

Located on the lower portion of the base 40 is a magnet 25) providedwith an armature 59, the end of which engages an inclined face 60 on apivoted lfifll iil mounted upon a pin 62 in the base -10. The other endof the pivoted lever (31 lies adjacent to the pin 47 carried by theratchet wheel 43. When the magnet 29 is operated to attract thisarmature 59, the spring surrounding the post 62 causes the pivot lever61 to catch and hold the said lever 55 in an attracted position, but ina position considerably less than its extreme movement. The catch pointon the lever 61 is shown at 63, and the other end of the armature leverlies adjacent to a series of contact springs 2324 32-33 and 35. \Vhenthe armature lever 59 is in its normal position these various springsmake electrical connections, as shown in the drawings. \Vhen thearmature lever is moved enough to be caught by the catch 63, theseconnections are shifted, as will be hereinafter described. The end whichmoves these contact springs is provided with a clapper 74.- adapted toengage a bell 75 whenever the armature 59 is actuated.

Fig. 6 shows the apparatus in a normal )osition. An impulse flowingthrough the magnet 29 will attract the armature so that it may be caughtby the lever 61 and will at the same time cause the clapper 74 to strikethe bell 75. After this takes place the magnet may be operated a numberof times resulting in ringing the bell 75, but without changing theelectrical connections due to such ringin The connection made between 61and 59 is a connection that is made after the ratchet wheel 43 has beenmoved from its 1 normal position. Assuming the wheel to be so advancedand the armature lever 59 to be cau ht and held by the lever 61, thereturn of tTie wheel 43 to its normal position will cause its pin 47 tostrike against the tail end pivoted lever 61 and disengage the catch 63from the armature lever 59. The contact springs before mentioned thenact to push the armature lever 59 outward against the inclined face 60.The in 47 'trikes the lever 61 just before it stri es the stop pin 48,and the momentum of the wheel 43, in returning to its normal position issnilicient to move the lever 61 so that when the armature lever 59engages the inclined face 60, such arrangement will hold the lever 61clear of the pin 47 with the result that the spring 46, which returnsthe ratchet wheel 43 to normal position need not be powerful enough toovercome the spring on the pin 62. which moves the lever 61. The generalobject to be obtained by this is to make the tension of the spring 46 aslight as possible with the result that very little force is required ofthe magnet M to advance the ratchet wheel.

livoted at a convenient place is a holding pawl 64, and projecting tailpiece 65 on the extreme end of the armature lever 41 engages thisholding pawl in such a way that when the armature lever is moved to theright to release the pawl 42 from the ratchet wheel 43 this tail piece65 lifts-the holding pawl 64: at the same time, thus leaving the'ratchet wheel 43 entirely free to return to its normal position. A verylight spring 66 serves to hold the holding pawl 64 in engagement withthe wheel 43 when not pushed outward by the tail piece 65.

Secured to the upturned lip of the base 40 is a. permanent magnet 67,see Figs. 2 and 9, the upper end of which is bent around through 180degrees so that the end face of this permanent magnet is directly abovethe armature h 1 and in line with the cores of the electromagnet M. Bentaround in this way the lilies of,force are directed to the armature in amore efficient manner than when the end of the magnet simply projectsover the armature in the ordinary way. The lower portion of thepermanent magnet 67 is adjustable by means of a screw 68 operating in aslot 69 in a magnet 67. By means of these parts the magnet 67 may be adjusted to or from the armature M with any degree of fineness that may bedesired, with the result that the armature is polarized in a moreefficient manner.

Referring now to Fig. 11, it will be assumed that the subscriber atstation, marked No. 1, desires to talk to the subscriber at station No.2, or with any other subscriber on the line, as may be desired. Theopera tion of effecting connection between two subscribers on the sameline is as follows: The calling subscriber turns his generator G whenthe current flows 12-3-4-5-6 7-89-1011121314.l516- 17-18-G. Thisoperates the drop 10 at the central ofiice and calls the operator there,who inserts a plug in the jack J and inquires what, station is wanted.The talking circuit, as far as the local station is concerned, is asfollows: induction coil K-19- receiver R--23456-8central offiec aparatus-l213l415l6-l7- 18- 20K.

The subscriber having informed the operator at the central ofiice thathe desires to talk to the subscriber at station No. 2, the operator willthen set her apparatus for stations 1 and 2 and turn the crank or movethe lever to send as many impulses over the party line 612 as there aresubscribers on the line, or a few more impulses than there are suchsubscribers. At the first impulse, each apparatus movcs forward onestep. As previously described, the connections .26 and 27 will be closedat this time for station No. 1. At the second step the similar contactswill be closed at station No. 2. The apparatus having been set for thesestations, there will be a secondary impulse accompanying the primaryimpulse from the central oilice. The primary impulses flow over theparty line 6-12 through the magnets M, which are bridged on the line(3-l as shown in Fig. 11. The secondary inipulse for these stations isan impulse which connects one of the lines to ground through a battery,the current flowing in this case from the central office through lines12 1326272829-ground back to the central oliice. This is an impulsethrough the magnet 29 which operates said magnet to attract its armatureto be caught hold of by the catch 63. This shifts the contact springs,as previously described, for station No. 1. In the same manner thecontact springs are shifted for station No. 2, but they are not shiftedfor any other station on the line because similar im )ulses are not sentfrom the central ofiice or selection of 5 any station other than the twoit is desired to place in telephonic connection. The advance of theswitching mechanism breaks the connection between the contact springs 3and 4, as )reviously described, with the re sult that the previouslydescribed talking and ringing circuits are broken at this point. Whenthis connection is broken at this point for a station in which themagnet 29 has not been operated, the receiver R for such station isshunted by a circuit as follows: R 2. -21-2-223-24-25-KR. For thestations, however, in which the magnet 29 has been operated so as tobreak the connection between 23 and 24, this shunt is broken 30 and thisexists for-stations No. 1 and No. 2, which we resume are the onesselected. In general e ect we may therefore say that the operation ofthe switching mechanism for a. given station operates to shunt thereceiver thereof, and thus cut it off from telephonic connection with aparty line, after which the operation of the magnet 29, in case suchmagnet is operated, results in a ain connecting the receivertelephonicall y to the line. If, however, the magnet 29 is not operatedthe receiver remains shunted with the result that the subscriber at thatstation is cut off from telephonic connection with the line.

The impulse which is described through magnet 29 causes a signal strokeon the bell at the station which is selected. The calling device usedusually has the latter and of its movement so arranged that it will senda series of impulses through the magnet which has been previouslyoperated. This is accomplished by reason of the connections 32 and 33.which are closed by the first operation of the magnet and serves asconnection 65 for magnet 29 as follows: from a central oflice over line12-13-l4-15-1617- 18H313233--34-29gr0und back to the central office. Itwill be observed that the central oliice sending impulses to line 12 andground would not reach its magnet 29 unless the connections 32 and 33had previously been closed in the manner before described. Theseconnections, therefore, serve as means for automatically signaling thecalled subscribers with a portion of the normal movement of the callingdevice used for selecting stations. Such calling operation, however, maybe a separate key which would send impulses over the circuit justdescribed. '10

The talking circuit between stations 1 and 2 as so far described wouldbe as follows: beginning at K of station No. 119-R-2- 3212223' 5-3645-6to 5 of station No. 2363523-22213-2R 19K20- H --1817-1615-1sl-13 12-backto 13 of station No. 1-1415 16-171S-H20-K. \Vhen through talking thesubscriber rings off, when the circuit closes as follows: G12-3--21--22-23353656clearing out drop at central oflice12131415--1G-17 l8-G. Theoperator then sends the impulse over the party line in the oppositedirection from those sent to operate the magnets M to advance theswitching mechanism. This impulse in the opposite direction moves thearmature lever 41 to the left and releases the various switchingmechanisms, as previously described so that their springs 46 may 9return them to their normal position. At stations No. l and No. 2 whichhave operated their magnets 29 and have their levers 61 moved so as tocatch-and hold the armatnres 59, the ends of such levers 61 will beadvanced far enough so that they will be struck a-blow by the pin 47 onthe ratchetwheel 43 just as it is arriving at its normal position andjust before it comes into contact with the stop pin 48. This blowreleases the catch levers (S1 for these two stations and permits thearmatures 59 to flow back to their normal position under the action ofthe springs 23 and 33, which press against the other end of the armaturelever and which were shifted in their connection by the attraction ofsaid armature by the, magnet 29. Connected to one of the branches whichgo to each station is an emergency key 70 which enables a subscriber tocall up the central office even when the line is in use by otherparties. F or example, the subscriber who needs to call the centraloilice in a case of emergency presses this key 70 and turns hisgenerator, when a current flows as follows: G127(l5fi8ccntral olliceapparatus back to 12l3 of the signaling station141516-1 7-13-( There ofcourse, a branch of this circuit going through his own magnet M and alsothrough the corrcspomling magnets of the other stations. The current inthe generator, however, does not operate thcsc magnets, or at leastoperates them to only a minute extent because this circuit passesthrough the central fixed part 16 and the contract springs 15, 17 oneach side of it. The instant the magnet begins to move, the armature 11thereof moves either spring 15 or spring 17 from its normal position incontact with the fixed part 16, with the result that this impulsethrough, such magnets is brokenbefore it accomplishes any result ofmoving the switching mechanism.

The holding pawl 64- is made of a pieceof spring metal bent back uponitself, as shown in Figs. 1 and 3, and the two branches of which areconnected together by a screw 80 which is under tension by the springaction of the metal. Tightenin the screw 80 tends to shorten the pawl bydrawing its holding end nearer to its pivot. Slacking u on the screwproduces the opposite effect 0 lengthcnin g the pawl. By thus adjustingthe holding pawl Get the teeth of the wheel 43 may be held duringoperation at any desired relationship to the driving pawl 42.

What I claim is:

1. The combination with a magnet, an armature lever moved thereby, andsprings for normally holding said lever in a mid-position, of a ratchetwheel arranged to be advanced from normal position by a movement of saidlever in one direction and to be released by a similar movement in theother direction, a spring for returning said wheel to normal positionwhen so released, a catch arranged to be released by a blow delivered bysaid wheel as it arrives at its normal position, said catch when not inoperation being normally held so as not to be touched by said wheel.

2. The combination with a magnet, an armature lever moved thereby, andsprin s for normally holding said ever in mi position, of a ratchetarranged to be advanced when said lever is moved in one direction and tobe released when movedin the other direction, a spring for returningsaid wheel to normal position when so released, a catch arranged to bestruck by said wheel to release the same as the wheel is arriving atnormal position, and an adjustable stop arresting said wheel at itsnormal position.

3. The combination with a ratchet wheel, means for advancing it, and aspring for returning it to normal position when released, of anarmature, a spring actuated catch for holding said armature in anattracted position, aprojection carried by said wheel and arranged tostrike and" release said catch when said wheel returnstowhich saidnormal position, and means by 1 said projeccatch is icld out of contactwit tion after said catch isreleased.

4. The combination with a ratchet wheel, means for advancing it, and aspring for returning itto normal position when released, of an armarranged to operate electrical connections when moved fromits normalposition, a'catch for holding it, in such moved position, means'forieleasing said catch upon the return of said wheel to its normalposition, and means by which said catch in its released position is heldclear from the means used for releasing it.

5. The combination with a ratchet wheel, means for advancing it, and aspring for returning to and beyond normal position when released, of aseries of contact devices, an arm arranged to actuate said devices whenmoved from its normal position, a catch for holding said arm in itsnormal position, means carried by said wheel for releasing said catch sothat the arm held thereby may return to its normal position, and meansby which said arm in its released position is held clear from the meansfor releasin 1t 6. 'l he combination with a ratchet wheel. means foradvancing it ste by step, and contact devices adapted to e temporarilvactuated at some particular step of such advance movement, of a piececarried by said wheel for engaging and actuating said contact devices,said piece being ad ustable by hand on said wheel and being held at anydesired position by spring tension.

7. The combination with a spindle and ratchet wheel secured together,means for advancing said wheel step by step, and contact devices adaptedto be actuated at some particular step of such advance. of a removablespring piece held by compression between said wheel and a shoulder onsaid spindle, said spring piece being adjustable by hand so that theprojecting end thereof may be located at any desired position on saidwheel with respect to'some fixed part thereof, and said projecting endbeing. arranged to engage and actuate said contact devices when movedpast them by the advance of said wheel.

'8. The combination with a spindle, a ratchet wheel secured thereto,means for advancing said wheel, and contact devices actuated by suchadvance, of a fork-shaped piece of spring metal adapted to be insertedetween said wheel, and a shoulder on said spindle and to'be held in anydesired positlon by friction, said fork-shaped piece havmg a projectingend for engaging said contact devices.

9. In the substation apparatus of a party line exchange, the combinationwith a rece ver normally in telephonic connection with the party linethrough a contact closable' by the switch hook, of a switching mechanismat the same station with the receiver and adapted upon advance to shuntthe receiver, a magnet adapted to break such shunt andto establish a newtelephonic connection for the receiver when actuated, said magnet alsobeing adapted to operate a signal receiver when. actuated, and means forholding the connections made by the actuaee i\'er normally in telephonicconnection with the party line through a contact closable by the switchhook, and a signaling ma net normally not in operative connection wit lithe line, vof a switching mechanism adapted upon advance to shunt thereceiver so as to destroy its telephonic connectionto ,the lineiand alsoto temporarily connect said magnet between "round and one branch of theline, electrica connections for breaking such shunt and establishing newtelephonic connections for the receiver and also for establishing a newconnection,forsaidmagnet, means by which anpperation of said magnetduring its temporary connection operates said electrical connections, acatch for holding such electrical connections in operatedcondition,'means by which said magnet may operate for signalim withoutinterfering wit 1 the connections held by said catch, means by which areturn of the switching mechanism .to its normal position will releasesaid catch so as to permit the connections held thereby to also returnto their normal position, and means for holding the released catch awayfrom the means for releasing it.

11. Ina arty line exchange, the combination with t 1e line limbs, aseries of electrically operated switching mechanism, each having itsoperating magnet in permanent bridge of said line limbs, and springs forreturning the switchin mechanisms to nor- 1 lIliLlPOSltlOIl when reeasedafter advance movement, said springs each being as hght' as will returnthe swltching mechanisms at electrically operated mechanism forgoverning the telephonic connection of the receiver to the line, andmeans for releasing the electrically o erated mechanism by the blow ldelivered y he switching mechanism when being stopped at thetermmat onof its re.- turn movement.

and a telephone receiver, of a connective mechanism for governing thetelephonic connection of the receiver to the line, a selective mechanismoperated by impulses sent over the line and serving to govern theoperation of the connective mechanism, means by which the connectivemechanism is held in an operated position after operation, a spring forreturn ng the selective mechanism to normal posltion when released, andmeans for releasin the connective mechanism by the blow cfizlivered bythe selective m a i h n amen memeh 1 stepp d ata aal Beaten,

J anew l3. Substation apparatus for party telephone-lines includingswitching mechanism, a detent for holding the switching mechanism in theosition to which it has been actuated, an electro-magnetic mechanismincluding a motor magnet and a signal-receiver for the substation, andserving to operate the said switching mechanism, to permit the detent toengage the same and for releasin the detent from connection with thesaid switching mechanism.

14. Substation apparatus for party telehone-lines, switchln mechanism, adetent or holding the switching mechanism in the position to which ithas been actuated, and electro-magnetic mechanism for releasing thedetent from connection with the switching mechanism, including a motormagnet and a signal receiver, which receiver serves to 0 erate theswitching mechanism, to permit the detent to engage the same.

15. The combination with a selecting device, and a signal receiver at alocal station of a party line exchange, of connections for operating theselecting device so as to connect the signal receiver to the line andfor operatin the signal receiver when so connected, a telephonicconnection for the station closed by the signal receiver, and meanscontrolled through the selecting device for breaking such telephonicconnection.

16. The combination with a central oliice, a series of local stations,and a party line, of a paratus at each station consisting of a telep onereceiver normally in operative relationship with the line through acontact closable by the switch hook, a signal receiver normally out ofoperative connection with the line, a selective mechanism permanently inoperative relationship with .a moderate speed, of a tele hone receiver,;

said line and so arranged that upon being op- 1 erated it will firstbreak the operative relationship between the telephone receiver and thel neand will subsequently place the signal receiver in operatlveconnection, and means j by Which an operation of the signal receiverWlll restore the operatlve relationship between the telephone receiverand the line. 12. The comblnat on with a party line 17. The combinationwith a central ollice, a series of local stations, and a party line, ofa telephone receiver at each station normally in operative relationshipwith said line through a contact closable by the switch hook, a signalreceiver at each station normally disconnected from the line, selectivedevices at each station simultaneously operated from the central ofiice,means by which anon operating said selective devices said to ephonerecelvers will have their operative relationship with the linesimultaneously interrupted, means by which further operation ,of theselective devices will conne t the signal receiver successively to theline so that they may be operated from the central oiiice, and means bywhich upon operating a signal receiver to call the subscriber at astation such operation will serve to reestablish the operativerelationship between the associated telephone receiver and the line.

18. The combination with a telephone line, of a telephone receivernormally capable of telephonic connection with the line, switchingapparatus adapted to restore telephonic capability to said receiver wheninterrupted, a signal receiver arranged to o erate the switchingapparatus but normal y disconnected from the line, and a selectivemechanism connected to the line and arranged to interrupt the telephoniccapability of the telephone receiver and to connect the signal receiverto the line so as to bring I about a. restoration of the telephoniccapability of the telephone receiver.

19. The combination with a party line, of a series of telephonereceivers each normally capable of telephonic connection with the line,selective mechanism for each receiver and connected to the line so thatall mechanisms are simultaneously operated, a signal receiver for eachtelephone, means by which the operation of the selective mechanismsserves to interrupt the telephonic capabilities of their respectivetelephones, contact devices operated by the selective mechanisms andarranged to complete connections successively to the signal receivers ofdifferent telephones so that the said signal receivers may be operated,and means by which the operation of any signal receiver serves torestore the telephonic capabilities of its respective telephone.

20. The combination with a arty line, a telephone receiver arranged to eplaced in telephonic relationship with the line, a signal receiver, acontact device controlling the telephonic relationship of the telephonereceiver with the line, means for operating the contact device by anoperation of the signal receiver, and a catch for holding the contactdevice in its normal position.

21. The combination with a party line, of a signal receiver providedwith devices for establishing its own connection with the line, andconnections through which an impulse may be sent for causing apreliminary operation of said signal receiver so as to establish suchconnection.

22. The combination with a party line, of a series of signal receiverseach of which is provided with devices for establishing its ownconnection with the line, and connections through which an impulse maybe sent for causing a preliminary operation of any one of said signalreceivers so as to establish such a connection therefor.

23. The combination with a central oilice, a series of local stations,and a party line, of a signal receiver at each station, contact devicesby which each signal receiver closes its connection with the line,selective apparatus at each station and controlled from the centraloflice, each selective apparatus being provided with means for closing apreliminary connection between the line and its as sociated signalreceiver, and means controlled from the central ofiice for sending animpulse through such preliminary conncction so as to cause the signalreceiver to operate its contact devices.

Signed at Chicago, Ill. this 27th day of May, 1909.

NILS EMEL NORSTROM.

Witnesses:

C. L. REDFIELD, CARRIE E. JORDAN.

Copies of this patent may be obtained for live cents each, by addressingthe Commissioner or Eatents,

Washington, D. 0.

